This invention relates generally to apparatus and methods for treating or coating a product with a working fluid or gas, and more particularly to apparatus and methods for pasteurizing and/or blanching food products.
Pasteurization and blanching of food products employ heat to kill harmful bacteria and enzymes thus improving food safety, shelf life, appearance, and quality. Often, the source of heat is steam or hot water. Typically, the food product is held at a specific time and temperature in a fluid medium to achieve the desired effect.
Existing apparatus for pasteurizing and blanching products employ a variety of approaches for subjecting the food product to heat. For example, some apparatus use a horizontal conveyor belt to transport the product through an insulated chamber where injected steam, a hot water bath, or hot water spray heat the product. Belt width, chamber length, product bed depth, and belt speed determine retention time and capability. Air locks, water baths, gates, and other means are used to contain steam in the chamber. As another example, some apparatus use a rotary-screw conveyor to transport the product through a cylindrical trough containing hot water. Often, a series of paddles at the end of the screw lift the product out of the trough.
While the existing approaches used for the pasteurization and blanching of food products can be effectively employed, further improvements remain desirable.